Fabius Maximus tried to illustrate the real-world application of the Dark Knight aphorism about men who 'just want to watch the world burn', and went seriously into the ditches by citing one Baju Bajrangi, a Hindu nationalist-fascist, terrorist and murderer. As Bill Quick points out, Bajrangi isn't a *textbook* pure-nihilist, in that he's clearly reacting to an initial atrocity with reciprocal atrocities. But I'm not satisfied with Quick's answer. It's incomplete, at least partially because the moral tableau established by that movie is incompletely described by Fabius Maximus. Let me explain.
The Dark Knight's action isn't just about a nihilist-terrorist and his hero-opposite. Rather, the movie presents us with The Joker, our man who 'wants to see the world burn', and two would-be heroes, established man-within-the-system District Attorney Harvey Dent, and the masked vigilante, Bruce Wayne/Batman. The Joker's goal isn't physical destruction for its own sake, but rather moral destruction. The world he wants to burn isn't tangible, physical, or ephiphomenal, but rather existential. He wants to burn down moral constructs, what he sees as social fictions. He's looking to find the flaw in the shining lie which is Harvey Dent, Pugnacious Hero-Reformer of the Corrupt City, and smash him utterly.
I can't remember where I picked this up, but somewhere out there is an archaic definition of "monster" as "in fiction, a person warped such that his or her personality presents a moral or ethical lesson." The Joker is convinced of the essential, irredeemable wickedness of man, and is looking for a person to make into his monster, a public soul to carve into the most shocking and monstrous of moral lessons. The middle of the Dark Knight, in which he places Dent into an impossible situation & shatters him into the disfigured, monstrous Two-Face, is The Joker's lit brand flung into the prepared bon-fire which is Gotham. Two-Face is the world set on fire, the atrocious response to atrocity.
In so far as the monster Two-Face is Harvey Dent in flames, he is the world on fire. He's an example of moral corruption and madness, whose very existence spreads the fire as sparks on rooftops in a crowded tinder-dry city. It's only when that fire-brand is extinguished and its very existence buried as in an unmarked grave by Wayne that The Joker's plot is defeated. In order to preserve the Heroic Dent, Wayne co-opts Two-Face's crimes & obscures The Joker's monster by subsuming him in Wayne's own moral lesson, a monster called the Batman.
There's a rich lode of metaphors in this narrative, and the Man Who Wants To See The World Burn is probably the most trivial of these. There are men like this throughout the academy, and all over Hollywood. Every third hip-hop, rock, and punk musician is probably somewhat inclined towards this point of view. Cheap nihilism is more common than not in the absence of proper moral instruction, and that particular duty has been neglected for the last hundred years and more. Socialized sociopathy is the end-result of the refusal to offer proper moral instruction on the part of our teachers and parents. The prisons are full of them, and if the streets are not even fuller, it's only because The Joker's belief that mankind is universally, essentially and irredeemably corrupt is at least as wrong as the belief that man is born free & everywhere lives in chains. Perhaps this is somewhat occluded by the relative rarity of socialized sociopaths with The Joker's corrupted-Calvinist view-point, as the more popular mind-sets are Rousseauian, in either the anarchic or totalizing trends.
But enough of that. We've had five generations of perfected brand-burning, fire-bombing, and pre-meditated arson. Men like Harvey Dent are even more common than the cheap nihilists, and Fabius Maximus's Bajrangi sounds like a Two-Face to me - not a man who wants to see the world burn, but rather the world itself on fire. He is the atrocious response to atrocity. Jokers are answerable on their own terms, as arsonists to be stripped of their matches, but what do you do with a man on fire? Extinguishing them seems often to be the simplest answer.